In the formation of a flexible walled receptacle of the type employed as a fuel tank for aircraft, one particularly difficult problem is encountered. That problem is to provide a satisfactory connection between attachments, such as connectors, gauges, pumps, conduits, etc. and the tank. Since the tank walls are flexible such attachments, in previous constructions, have readily pulled loose due to the lack of a strong bond between the rigid material of the attachment and the elastic interface with the tank. Materials, such as Nylon, which have high elongation when stressed to even a small fraction of their ultimate strength, tend to stretch away from the interface bond when the bond substrate is rigid, causing a peel type failure at loads far below the basic material strength. Of many attempts to overcome the problem of transferring loads from a rigid fitting to an elastic bladder, only one has had significant success and it is exemplified by U.S. Pat. No. 3,537,732 to the present applicant. The fitting covered by such patent is capable of surmounting the load transfer problem but it is expensive and difficult to manufacture, it is excessively heavy, sparks may be generated and create an explosion hazard when the fitting is struck by high velocity projectiles, and large holes, through which fuel can escape, may be left after a bullet has struck. One of the aims of this invention is to avoid the aforementioned deficiencies.
The field of this invention is generally exemplified by the following patents:
______________________________________ #2,366,442 to Cunningham #2,441,009 to Cunningham #2,772,101 to Smith #2,911,236 to Thiboult ______________________________________